Use of a magnetron with a magnetron target to produce a vapor that can be deposited on a substrate is known and widely used. To use this technique it has been known to position substrates in the vicinity of magnetron targets and to allow sputter produced vapors to expand and hereby contact and be deposited on substrate surfaces. Additionally, bias voltages have been applied to substrates to draw ionized sputtered materials to substrates and thereby control ion energy and resulting surface and film properties.
Use of magnetic fields to control deposition processes also has been utilized. Magnetic fields created adjacent and between magnetron targets and substrates have been used to guide and focus magnetron produced ionized sputter vapors. To be effective in this guiding and focusing, therefore, it is necessary to produce magnetron generated sputter vapors having high ionized fractions. This requirement has necessitated use of pulsed magnetrons such as High Power Impulse Magnetron Sputtering (HIPIMS) systems as opposed to direct current (DC) or radio-frequency (RF) magnetron sputtering which, depending on power level, discharge geometry, magnetron target material and magnetic field geometry typically produce much less than 10% ionization of sputtered material.
A further benefit of HIPIMS systems is the realization of highly ionized vapors without production of target material droplets—such as may be produced by cathodic arc evaporation. As typically operated, HIPIMS systems produce sputter discharge vapors having pulse widths on the order of 100 microseconds (μs) or less. Accordingly, magnetic fields applied by electric current passing through field coils between magnetron targets and substrates are driven with Direct Current (DC) electric power. A reason why DC electric power is used as opposed to pulsed electric currents that could be increased over DC electric power to produce increased magnetic fields is because of self-inductance effects that decrease the produced magnetic field in time regimes on the order of 100 μs magnetron pulses. This consequence of self-inductance has resulted in use of guiding and focusing magnetic field strengths that are produced by applied DC electric power.